Fifth wheel hitch mechanisms are commonly used to couple a towed trailer or recreational vehicle to a towing vehicle. A towing vehicle may include, but is not limited to, a semi-tractor, tow truck, or pickup truck. Generally, the towing vehicle will include a latching assembly, also called a fifth wheel hitch. For example, in the case of a pickup truck, a latching assembly is attached to the floor of the truck bed. The item to be towed includes a kingpin, which the latching assembly engages. In some cases, this arrangement is reversed with the kingpin attached to the towing vehicle and the latching assembly or hitch attached to the item to be towed. Accordingly, the latching assembly captures and locks the kingpin in place in order to pull the towed vehicle.
A dangerous situation occurs when a towed item uncouples from a towing vehicle during use. However, fifth wheel latching assemblies of the prior art do not provide secondary locking mechanisms to prevent decoupling of the kingpin in the event that the hitch assembly fails. U.S. Pat. Nos. 7,896,363 to Cockram et al. and 5,839,745 to Cattau et al. disclose fifth wheel hitch devices with single jaw members to hold a kingpin in place. In these devices, should the jaw members fail, decoupling will occur. In other previous fifth wheel latching assemblies, such as those described in U.S. Pat. Nos. 7,543,837 to Crawley and 6,935,650 to Grinde et al., two jaw members are employed to lock a kingpin in place. However, these devices do not include a second locking means to prevent decoupling in the event that the two jaw members separate.
In another example, U.S. Pat. No. 8,132,825 to Choquette et al. discloses a fifth wheel hitch including two opposing jaw pieces, a tumbler, and a latch. The two opposing jaw pieces are biased in an open, unlocked position by a spring. The tumbler is the only locking mechanism and, in the locked position, holds the jaw pieces closed. Should the tumbler fail, the jaw pieces will be pulled to their open positions by the spring, thus allowing decoupling of the hitch and kingpin.
U.S. Pat. No. 8,210,558 to Mann et al. discloses a fifth wheel hitch having a secondary lock assembly. However the Mann et al. secondary lock assembly does not solve the problem of preventing kingpin decoupling in the event that the primary lock assembly fails. Specifically, the Mann et al. assembly includes a jaw member which captures the kingpin. A locking wedge holds the jaw member in place to lock the kingpin for towing. When the wedge member is not in place, the jaw member is held open by a spring. The wedge is connected to a tie bar, which is in turn connected to a pull bar located near the front (towards the towing vehicle) of the fifth wheel hitch. A locking mechanism is present to lock the pull bar, and accordingly the tie bar and wedge, in the locked position. However, should the wedge, tie bar, or pull bar fail, the locking mechanism will not prevent decoupling of the kingpin by the hitch. Moreover, the secondary locking mechanism disclosed in Mann et al. must be manually activated by the user.
In another example, U.S. Pat. No. 5,257,796 to Thorwall et al., which discloses an integrated cam lever and handle lock fifth wheel, locking of a single locking mechanism is automatic upon kingpin insertion. The Thorwall et al. device discloses a single jaw, cam arm, locking plunger, release arm, and release handle. In the locked position, the locking plunger engages the single jaw and is held in place by the positions of the cam arm, release arm, and release handle. However, the single jaw requires engagement with the plunger to lock the kingpin in place. Therefore, failure of the plunger or locking mechanism will cause decoupling of the kingpin by the jaw element.
Accordingly, there is a need in the art for a fifth wheel latching assembly that provides two locking mechanisms which both independently prevent uncoupling of a kingpin from the latching assembly. Moreover, there is a need in the art for a fifth wheel latching assembly wherein two locking assemblies are automatically locked upon insertion of a kingpin without manual activation by the user. The fifth wheel latching assembly should include few moving parts and allow for quick coupling and decoupling of the latching assembly and kingpin.